A silsesquioxane derivative has excellent characteristics in terms of thermal resistance, electric insulating property, water repellency, weather resistance and anti-flammability. And therefore it is paid attention as a modifying agent for common organic polymers and an additive for coating materials and has so far widely been investigated. It has been reported that this silsesquioxane derivative is obtained by hydrolyzing an organic silicon compound having three hydrolyzable groups and then subjecting it to dehydration and condensation. According to, for example, a general remark described in Literature 6 written by Baney et al., it is confirmed that the existences of silsesquioxane derivatives having a ladder structure, a cage structure, a partial cage structure and a random structure.
A commercial product of silsesquioxane derivative having a random structure is present, and this is widely used in general. However, these substituents are usually methyl or phenyl and do not have reactive groups, and therefore they can not be incorporated into a part to be modified by reaction. They can be incorporated only by blending and therefore are bled out depending on the use conditions, and this means that the characteristics provided by adding a silsesquioxane derivative are lost.
A process for introducing methacryloyloxy group into one of substituents to apply it to a resist material has been disclosed in Literature 1 and Literature 2. A process for producing a silsesquioxane derivative having an alcoholic hydroxyl group has been disclosed in Literature 3. At the process, the alcoholic hydroxyl group is derived by reaction of epoxy group and water in the process which a trialkoxysilane having epoxy group is hydrolyzed and polycondensed. However, these processes have involved the problems that the compounds, which can be used among silicon compounds having a reactive functional group, are restricted and that a functional group, which may be hydrolyzed, can not be introduced as described in Literature 3.
On the other hand, a process in which a silsesquioxane derivative having a hydrosilyl group is used as a raw material and this is subjected to hydrosilylation with a compound having a functional group and an unsaturated hydrocarbon group, is known as a process for producing a silsesquioxane derivative having a functional group. Literature 4, Literature 5 and Literature 7 are examples in which the silsesquioxane derivative having a hydrosilyl group is described. Some of the silsesquioxane derivatives having a hydrosilyl group disclosed in these literatures, require a specific apparatus for using fuming sulfuric acid in producing them. Further, even if a silsesquioxane derivative having a functional group can be produced, it is not easy to control a structure thereof as desired.
Disclosed by Aguskar et al. in Literature 8 was a process in which a cage type silsesquioxane derivative is produced by carrying out reaction in the presence of iron chloride using methanol as a solvent. In this production process, however, the production can be carried out only on a very dilute condition, and the volume efficiency is low. In addition thereto, the yield is low as well, and therefore there has been the problem that the product is very expensive. In recent years, commercially available is a compound which is a silsesquioxane derivative having a partially collapsed cage type structure, a reactive substituent and a non-reactive substituent which is cyclohexyl, cyclopentyl or isobutyl (Literature 9).
Lichtenhan et al. have obtained a silsesquioxane derivative having a reactive functional group by a reaction of a silsesquioxane derivative having a partial cage structure and alkoxysilane in the presence of a hydroxide of alkaline metal or ammonium hydroxide as a catalyst (Literature 10). However, alkoxysilane is usually produced from chlorosilane, and therefore it is apparent that the cost is high as compared with that of a production process in which chlorosilane is directly reacted.                Literature 1: Japanese Patent Application Laid Open No. 12057/1982        Literature 2: Japanese Patent Application Laid Open No. 213728/1984        Literature 3: Japanese Patent Application Laid Open No. 87834/1998        Literature 4: Japanese Patent Application Laid Open No. 86017/1985        Literature 5: Japanese Patent Application Laid Open No. 340812/1994        Literature 6: Chem. Rev. 95, 1409 (1995)        Literature 7: J. Am. Chem. Soc., 92, 5586–5588 (1970)        Literature 8: J. Matter. Chem., 3 (12), 1319–1325 (1993)        Literature 9: POSS CHEMICAL CATALOG, Hybrid Plastics        Literature 10: U.S. 2003/0055193 A1 (Mar. 20, 2003)        